On the other hand, if a protein gains cysteine, an active and reducing agent, this might enhance its capability to neutralize ROS in tumor environment (Anoosha, Sakthivel, & Michael Gromiha, 2016; Halasi et al., 2013; Tsuber, Kadamov, Brautigam, Berglund, & Helleday, 2017). Proteomic changes by the protein carrying missense mutation may help the cancer cells adapt to environmental pressure (Szpiech et al., 2017). Even though different types of cancers have their properties, they might share some substitution patterns. Between breast and digestive tract cancers, the amino acid substitution spectrum is similar, dominated by glutamic acid altered to lysine (Tan, Bao, & Zhou, 2015).